interface Dog {
    name: string;
    age: number
}

// extends 继承
interface Cat extends Dog {
    like: string
}

let c1: Cat = {
    like: "吃鱼",
    name: '小花',
    age: 2
}


// 继承多个接口时  接口与接口之间 用逗号隔开
interface Fish extends Dog, Cat {
    say(): number
}

let f1: Fish = {
    name: "小鱼",
    age: 1,
    like: "鱼粮",
    say() {
        return 123
    }
}